H C Shin

Hallym University, Sŏul, Seoul, South Korea

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Publications (20)42.8 Total impact

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    ABSTRACT: Cellular and biochemical responses of the pectoral muscle to variation in seasonal activity were studied in the bat, Murina leucogaster ognevi. We collected bats in mid-hibernation (February), end-hibernation (April), and mid-summer (August) to track major activity periods in their annual cycle. Our findings indicated that myofiber cross-sectional area decreased to 68% between mid- and end-hibernation, but returned to the winter level in mid-summer. Total soluble protein and total RNA concentrations were not altered over these sampling periods. Oxidative potential gauged by citrate synthase activity increased 1.47-fold from mid- to end-hibernation and then remained at the similar level in mid-summer. Glycolytic potential gauged by lactate dehydrogenase activity changed little between mid- and end-hibernation but increased 1.42-fold in summer, compared with the winter level. Thus, the myofibers underwent disuse atrophy during hibernation, while enzymatic catalytic function recovered towards the level of mid-summer.
    Comparative Biochemistry and Physiology - Part A Molecular & Integrative Physiology 07/2000; 126(2):245-50. DOI:10.1016/S1095-6433(00)00203-8 · 2.37 Impact Factor
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    ABSTRACT: Administration of the excitotoxin kainate produces seizure activity and selective neuronal death in various brain areas. We examined the degeneration pattern of hippocampal neurons following systemic injections of kainate in the hamster and the rat. As reported, treatment with kainate resulted in severe neuronal loss in the hilus and CA3 in the rat. While the hilar neurons were also highly vulnerable to kainate in the hamster, neurons in the CA1 area, but not CA3, were highly sensitive to kainate. In both animals, immunoreactivity to anti-p50 nuclear factor kappa B antibody was increased in nuclei of the hilar neurons within 4 h following administration of kainate. Kainate treatment also increased the nuclear factor kappa B immunoreactivity in hamster CA1 neurons and rat CA3 neurons 24 h later. Neurons showing intense nuclear factor kappa B signal were stained with acid fuchsin. Kainate also increased DNA binding activity of p50 and p65 nuclear factor kappa B in the nuclear extract of the hippocampal formation as analysed by electrophoretic mobility shift assay in the hamster, suggesting that activation of nuclear factor kappa B may contribute to kainate-induced hippocampal degeneration. Administration of 100 nmol dizocilpine maleate 3 h prior to kainate attenuated kainate-induced activation of nuclear factor kappa B and neuronal death in CA1 in the hamster. The present study provides evidence that the differential vulnerability of neurons in the rat and the hamster hippocampus to kainate is partly mediated by mechanisms involving N-methyl-D-aspartate-dependent activation of nuclear factor kappa B.
    Neuroscience 09/1999; 94(1):83-91. DOI:10.1016/S0306-4522(99)00196-7 · 3.33 Impact Factor
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    ABSTRACT: Activity-dependent changes of conduction velocity (CV) and conduction block in single A(delta) fibers of primary afferent neurons were characterized in a rat model of neuropathy (NP). Injured dorsal root (DR) fiber in NP rats exhibited profoundly greater decreases of CV following impulse activity than did DR fiber in normal rats. Activity-dependent conduction block was absent up to 100 Hz of activity rate in DR fiber of NP rats, but was present above 25 Hz in normal rats. Profiles of activity dependence in sciatic fibers were similar in both NP and normal rats. These results suggest that nerve injury may alter activity-dependent hypoexcitability of A(delta) DR fibers. Furthermore, this excitability change may be responsible for the elevated pain perception in neuropathy.
    Neuroreport 11/1997; 8(15):3201-5. DOI:10.1097/00001756-199710200-00004 · 1.64 Impact Factor
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    ABSTRACT: The effects of topical application of interleukin-6 (IL-6) on the short and long latency evoked unit responses of the neurones in the primary somatosensory (SI) cortex were determined quantitatively in anaesthetized rats. IL-6 (0.01, 0.1, 1.0 units) significantly suppressed (-15.13 +/- 3.4%) short latency afferent sensory responses, while it induced profound facilitation (+464.74 +/- 132.7%) of long latency responses in a dose-dependent manner. IL-6-induced afferent modulations fully recovered by 60 min after drug administration. In control experiments, saline solution containing 0.2% bovine serum albumin, used as a vehicle, did not affect afferent sensory transmission. Implications of these results are discussed with reference to the different somatosensory functions of short and long latency response components in the SI cortex.
    Neuroreport 10/1997; 8(13):2841-4. DOI:10.1097/00001756-199709080-00007 · 1.64 Impact Factor
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    ABSTRACT: Activity-dependent changes of the conduction latency of single A beta fibers of primary afferent neurons were characterized in both neuropathic (L4 and L6 ligated) and normal rats. Activity-dependent increases in conduction latency of dorsal root fibers in neuropathic rats were significantly stronger than those in normal rats. Different profiles of activity dependence were also observed between injured and adjacent intact dorsal root fibers of neuropathic rats. However, activity-dependent latency changes in sciatic nerves distal to the dorsal root ganglion were not different between neuropathic and normal rats. These results suggest that partial nerve injury induces activity-dependent excitability changes in the dorsal root fibers of neuropathic rat and that these changes may be responsible for the altered sensory processing such as those seen in allodynia.
    Neuroreport 09/1997; 8(12):2813-6. · 1.64 Impact Factor
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    ABSTRACT: Single unit responses of the primary somatosensory (SI) cortical neurons to the stimulation of the forepaw single digit were monitored in anesthetized rats before and after subcutaneous injection of lidocaine to an ipsilateral homologous receptive field (IHRF). Quantitative determination of the temporal changes of afferent sensory transmission was done by analyzing poststimulus time histograms of unit responses. Temporary deafferentation to the IHRF induced immediate, but reversible suppression of afferent sensory transmission in the SI cortex and this suppression lasts up to 35 min post-deafferentation period (during 10-15 min, -21.81 +/- 5.9%, P < 0.01). This result suggests that temporary absence of afferent inflow from the digit to the SI cortex may exert interhemispheric modulation of afferent sensory transmission in the opposite somatosensory cortex of anesthetized rats.
    Neuroscience Letters 07/1997; 230(2):137-9. DOI:10.1016/S0304-3940(97)00486-2 · 2.06 Impact Factor
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    ABSTRACT: The effects of acute lowering of body temperature on afferent sensory transmission to the primary somatosensory cortex were determined quantitatively in anaesthetized rats and hamsters. Rats showed no change in afferent sensory transmission until 27 degrees C, but dramatic suppression between 26 degrees C and 22 degrees C, reaching 100% inhibition at 21 degrees C. Hamsters exhibited gradual suppression of sensory transmission from 34 degrees C to 18 degrees C, reaching 95% inhibition at 18 degrees C. Differential effects were also observed during rewarming up to 37 degrees C. Response latencies were also differentially affected during hypothermia in rats and hamsters. These results suggest the presence of inherently different neural mechanisms to process somatosensory information during transient lowering of body temperature between hibernators and non-hibernators.
    Neuroreport 01/1997; 8(1):41-4. DOI:10.1097/00001756-199612200-00009 · 1.64 Impact Factor
  • M H Won, Y S Oh, H C Shin
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    ABSTRACT: The presence of somatostatin-like immunoreactive neurons was examined in the rabbit vestibular ganglion by using immunohistochemical techniques. About 22% (n = 153) of the total ganglion cells (n = 699) examined were somatostatin-immunoreactive and they were diffusely present throughout the ganglion. Majority of the somatostatin-immunoreactive cells were large (long diameter, 23-31 microns, 74%; short diameter, 20-25 microns, 76%) and they had oval or spherical cell bodies with well developed Nissl's body. However, about 78% (n = 546) of the total ganglion cells examined were not immunoreactive to the somatostatin. The presence of the somatostatin-immunoreactive neurons in the vestibular ganglion suggests a possibility that somatostatin may be involved in the modulation of afferent sensory transmission from the vestibular organ of the rabbit.
    Neuroscience Letters 11/1996; 217(2-3):129-32. DOI:10.1016/0304-3940(96)13088-3 · 2.06 Impact Factor
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    ABSTRACT: Single unit recordings were made from the ventral posterior lateral thalamus of anaesthetized rats to characterize responses to the activation of new receptive fields induced by either local anaesthesia or amputation. Receptive fields confined to single digits were identified and evoked unit responses to the stimulation of single digits were quantitated before and after deafferentation. Although both methods of denervation rapidly induced similar new receptive fields from the adjacent single digit, they exhibited quite different temporal changes of the evoked unit responses from new receptive fields. This difference in the evoked unit responses from the new receptive fields may be related to either the different nature or the outcome of the two types of deafferentation.
    Neuroreport 01/1996; 7(1):33-6. DOI:10.1097/00001756-199512000-00007 · 1.64 Impact Factor
  • Chungkil Won, H J Park, H C Shin
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    ABSTRACT: The effect of topical application of human recombinant interleukin-1 beta (IL-1) on afferent sensory transmission to the neurones in the primary somatosensory (SI) cortex was determined in anesthetized rats. Quantitative determination of the effect of IL-1 was made by generating post-stimulus time histograms of unit responses to the stimulation of receptive field. IL-1 (0.01, 0.1, 1.0 U) significantly facilitated afferent sensory transmission in SI cortical neurones (n = 22). IL-1-induced facilitation fully recovered by 60 min after drug. In control experiments (n = 10), saline solution containing 0.2 bovine serum albumin, used as a vehicle, did not affect afferent sensory transmission. Our results suggest that IL-1 may be involved in the processing of afferent sensory information in the SI cortex of rats.
    Neuroscience Letters 01/1996; 201(3):255-8. DOI:10.1016/0304-3940(95)12185-4 · 2.06 Impact Factor
  • H J Park, C K Won, K H Pyun, H C Shin
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    ABSTRACT: The effect of topical application of interleukin 2 (IL-2) on afferent sensory transmission to the neurones in the primary somatosensory (SI) cortex was determined quantitatively in anaesthetized rats. IL-2 (0.1, 1.0, 5.0 units) significantly suppressed afferent sensory transmission in SI cortical neurones (n = 19) in a dose-dependent manner. IL-2-induced suppression fully recovered by 60 min after drug. In control experiments, saline solution containing 0.2% bovine serum albumin, used as a vehicle, did not affect afferent sensory transmission. Our results suggest that IL-2 and its receptor present in the SI cortex may be involved in the processing of afferent sensory information.
    Neuroreport 06/1995; 6(7):1018-20. DOI:10.1097/00001756-199505090-00017 · 1.64 Impact Factor
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    ABSTRACT: Compound action potentials (CAPs) of A- and C-fibres were recorded from isolated sciatic nerves of the rat to determine whether lidocaine-induced phasic impulse block was affected by low doses of capsaicin. Preceding impulse activity produced phasic reductions of the amplitudes of both A- (5.7 +/- 1.3%) and C-CAPs (20.7 +/- 7.0%) in drug-free solution. Capsaicin alone (50 microM) did not change the activity-induced reductions of the heights of both CAPs (A-CAP: 6.2 +/- 1.7%, C-CAP: 22.3 +/- 8.0%). Lidocaine (100 microM) caused differential phasic blocks between the A-CAP (20.1 +/- 3.7%; n = 7) and the C-CAP (33.8 +/- 4.9% n = 7). Lidocaine's phasic impulse block was potentiated after 30 min of subsequent capsaicin administration (A-CAP: 40.6 +/- 4.7%, n = 7; C-CAP: 48.8 +/- 5.5% n = 9). Capsaicin's phasic potentiating effects were reversed after 30 min of washing. These results suggest that capsaicin may be a useful agent for the reversible potentiation of phasic impulse blockade by lidocaine.
    Pharmacological Research 08/1994; 30(1):73-9. DOI:10.1016/1043-6618(94)80089-8 · 3.98 Impact Factor
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    ABSTRACT: Compound action potentials (CAPs) of A- and C-fibers were recorded from isolated sciatic nerves of the rat to determine whether tonic block of impulse conduction induced by lidocaine was affected by low doses of capsaicin. Capsaicin alone (50 microM) did not change the CAPs of either A- or C-fibers. Although the lower concentrations of capsaicin (5-30 microM) caused no change of the tonic blocking action of lidocaine, 30 min of 50 microM capsaicin administration did induce a significant potentiation of tonic block. Capsaicin's potentiating effects were partially reversed after 30 min of wash. These results suggest that capsaicin may be a useful agent for the potentiation of impulse blockade by lidocaine.
    Neuroscience Letters 07/1994; 174(1):14-6. DOI:10.1016/0304-3940(94)90107-4 · 2.06 Impact Factor
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    ABSTRACT: Single neurons were recorded in the forepaw area of the primary somatosensory (SI) cortex of awake rats during rest and running behavior. Locomotor step cycle dependent changes of the transmission of the short (4.5 +/- 0.1-10.5 +/- 0.1 ms, SEURs) and the long (10.6 +/- 0.6-28.5 +/- 2.3 ms, LEURs) latency evoked unit responses were tested by generating post-stimulus time histograms of these neurons' responses to stimulation through electrodes chronically implanted under the skin of the forepaw. Times of footfall were determined by way of frame-by-frame analyses of video recordings, and peri-footfall histograms were generated to differentiate a total of 55 SI cortical neurons into two types: footfall responsive (n = 37) and footfall unresponsive (n = 18) neurons. Peri-footfall gating patterns were determined for both types of cells. The SEURs and the LEURs showed significantly different phasic sensory modulation patterns. A major difference in sensory modulations between footfall responsive and footfall unresponsive cells was noted during the swing phase of the locomotor step cycle. In footfall responsive cells, the SEURs were suppressed most strongly just after footfall, while the LEURs were phasically suppressed following both footfall and footoff. The SEURs were disinhibited during the swing phase. In footfall unresponsive cells, the SEURs were tonically suppressed during the whole locomotor step cycle phases. However, the LEURs were phasically facilitated during the early swing phase.(ABSTRACT TRUNCATED AT 250 WORDS)
    Neuroscience Research 07/1994; 19(4):419-25. DOI:10.1016/0168-0102(94)90083-3 · 2.15 Impact Factor
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    ABSTRACT: Single neurons were recorded in the forepaw area of the ventroposterolateral (VPL) thalamus of awake rats during rest and running behaviors. Locomotor step cycle dependent changes of the transmission of the short (4.0 +/- 0.1-10.1 +/- 0.3 ms, SEURs) and the long (10.2 +/- 0.2-26.0 +/- 2.1 ms, LEURs) latency somatic sensory responses were tested by generating post-stimulus time histograms of these neurons' responses to stimulation through electrodes chronically implanted under the skin of the forepaw. The magnitudes of firing during these responses were measured and normalized as percent increases over background firing. Times of footfall were determined through frame-by-frame analyses of video recordings and peri-footfall histograms were generated to differentiate a total of 40 VPL thalamic neurons into two types, footfall responsive (n = 21) and unresponsive (n = 19) neurons. Perifootfall gating patterns were determined for both types of cells. The SEURs and the LEURs showed significantly different phasic sensory modulation patterns across the locomotor step cycle. Major difference of the sensory modulations between footfall responsive and footfall unresponsive cells was noted during swing phase of the locomotor step cycle. In footfall responsive cells, the SEURs were suppressed most strongly just after footfall, while the LEURs were tonically suppressed during late stance and swing phases. The SEURs were disinhibited during the swing phase, while the LEURs were disinhibited during the middle stance phase. In footfall unresponsive cells, the LEURs were suppressed more strongly around footfall event than the SEURs were.(ABSTRACT TRUNCATED AT 250 WORDS)
    Neuroscience Research 08/1993; 17(2):117-25. DOI:10.1016/0168-0102(93)90089-9 · 2.15 Impact Factor
  • H C Shin, John K. Chapin
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    ABSTRACT: Single unit recordings were used to map the spatial distribution of motor (MI) cortical influences on thalamic somatosensory relay nuclei in the rat. A total of 215 microelectrode penetrations were made to record single neurons in tracks through the medial and lateral ventroposterior (VPM and VPL), ventrolateral (VL), reticular (nRt), and posterior (Po) thalamic nuclei. Single units were classified according to their: 1) location within the nuclei, 2) receptive fields, and 3) response to standardized microstimulation in deep layers of the forepaw-forelimb areas of MI cortex. For mapping purposes, only short latency (1-7 msec) excitatory neuronal responses to the MI cortex stimulation were considered. Percentages of recorded thalamic neurons responsive to the MI stimulation varied considerably across nuclei: VL: 42.6%, nRt: 23.0%, VPL: 15.7%, VPM: 9.3%, and Po: 3.9%. Within the VPL, most responsive neurons were found in "border" regions, i.e., areas adjacent to the VL, and (to a lesser extent) the nRt and Po thalamic nuclei. The same parameters of MI cortical stimulation were used in studies of corticofugal modulation of afferent transmission through the VPL thalamus. A condition-test (C-T) paradigm was implemented in which the cortical stimulation (C) was delivered at a range of time intervals before test (T) mechanical vibratory stimulation was applied to digit No. 4 of the contralateral forepaw. The time course of MI cortical effects was analyzed by measuring the averaged evoked unit responses of the thalamic neurons to the T stimuli, and plotting them as a function of C-T intervals from 5-50 msec. Of the 30 VPL neurons tested during MI stimulation, the average response to T stimulation was decreased a mean 43%, with the suppression peaking at about 30 msec after the C stimulus. This suppression was more pronounced in the VPL border areas (-52% in areas adjacent to VL and nRt) than in the VPL center (-25%).
    Brain Research Bulletin 03/1990; 24(2):257-65. DOI:10.1016/0361-9230(90)90213-J · 2.97 Impact Factor
  • H C Shin, John K. Chapin
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    ABSTRACT: Single units (n = 135) were recorded in the ventroposterolateral nucleus of the thalamus in awake rats. The responsiveness of neurons to sensory activation during rest and treadmill locomotion was tested by stimulation through electrodes implanted under the skin of the forepaw. The averaged evoked unit response was suppressed by a mean 31% during movement as compared with rest. This is to be compared with the mean 71% sensory suppression observed previously in the somatosensory cortex. These findings are consistent with the hypothesis that sensory information ascending to, and within the SI cortex is successively modulated at several levels during movement.
    Neuroscience Letters 02/1990; 108(1-2):116-20. DOI:10.1016/0304-3940(90)90716-M · 2.06 Impact Factor
  • H C Shin, J K Chapin
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    ABSTRACT: Single neurons were simultaneously recorded in the forepaw areas of the primary somatosensory (SI) cortex and ventroposterolateral (VPL) thalamus of awake rats during rest and running behaviors. Movement dependent changes in somatic sensory transmission were tested by generating post-stimulus histograms of these neurons' responses to stimulation through electrodes chronically implanted under the skin of the forepaw, while the animal ran on a timed treadmill. As viewed in post-paw-stimulus histograms, the evoked unit responses (EURs) could be differentiated into short (4.5 +/- 0.1-10.9 +/- 0.2 ms) and longer (12.9 +/- 0.4-31.3 +/- 0.9 ms) latency components ("SEURs" and "LEURs", respectively). The magnitudes of firing during these responses were measured and normalized as percent increases over background firing. By comparison with resting behavior, treadmill movement suppressed both SEURs and LEURs in the thalamus, as well as the cortex. The SEURs, however, were much more strongly suppressed in the SI cortex (-48.3 +/- 2.7%) than in the VPL thalamus (-28.1 +/- 6.7%). By contrast, similar magnitudes of suppression of LEURs were found in the SI (-25.8 +/- 8.6%) and VPL (-26.5 +/- 11.1%). These results suggest that the suppression of LEURs observed in the SI cortex may result from modulatory actions on subcortical circuits. Major suppression of SEURs, on the other hand, may occur intracortically, with a minor component occurring subcortically. Thus, VPL thalamus and SI cortex in the rat appear to be differentially subject to movement related modulation of sensory transmission.
    Experimental Brain Research 02/1990; 81(3):515-22. DOI:10.1007/BF02423500 · 2.17 Impact Factor
  • H C Shin, John K. Chapin
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    ABSTRACT: We have used single-unit recording techniques to map the spatial distribution of the primary somatosensory (SI) cortical influences on thalamic somatosensory relay nuclei in the rat. A total of 193 microelectrode penetrations were made to record single neurons in tracks through the medial and lateral ventroposterior (VPL and VPM), ventrolateral (VL), posterior (Po), and reticular (nRt) thalamic nuclei. Single units were classified according to their (1) location within the nuclei, (2) receptive fields, and (3) response to standardized microstimulation in deep layers of the SI cortical forepaw areas. The SI stimulation produced short-latency (1- to 7-msec) excitatory responses in different percentages of neurons recorded in the following thalamic nuclei: VPL, 42.0%; Po, 25.0%; nRt, 16.4%; VL, 13.6%; and VPM, 9.9%. Within the VPL, the highest proportion of responsive neurons was found in the anterior region. Although most of the VL region was unresponsive, the caudal subregion bordering the rostral VPL showed some responsiveness (13.6% of neurons). In general, the spatial pattern of corticothalamic influences appeared to reciprocate the known thalamocortical connection patterns, but with a heterogeneity that was unpredicted. The same parameters of SI cortical stimulation were used in studies of corticofugal modulation of afferent transmission through the VPL thalamus. A condition-test (C-T) paradigm was implemented in which the cortical stimulation (C) was delivered at a range of time intervals before test (T) mechanical vibratory stimulation was applied to digit 4 of the contralateral forepaw. The time course of cortical effects was analyzed by measuring the averaged evoked unit responses of thalamic neurons to the T stimuli, and plotting them as a function of C-T intervals from 5 to 50 msec. Of the 20 VPL neurons tested during SI stimulation, the average response to T stimulation was decreased a mean of 36%, with the suppression peaking (at 49% inhibition of the afferent response) about 15 msec after the C stimulus. Considerable rostrocaudal variation was observed, however. Whereas neurons in the rostral VPL (near VL) were strongly inhibited (-69%), neurons in the middle and caudal VPL exhibited facilitations at long and short C-T intervals, respectively. This study establishes a specific projection system from the forepaw region of SI cortex to different subregions of the VPL thalamus, producing specific temporal patterns of sensory modulation.
    Somatosensory and Motor Research 02/1990; 7(4):421-34. DOI:10.3109/08990229009144717 · 0.58 Impact Factor
  • H C Shin, John K. Chapin
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    ABSTRACT: The major aim of this study was to define the topography of descending motor cortical influences on the dorsal column nuclei of the rat. A total of 1442 single neurons were recorded throughout the rat cuneate (Cu) or external cuneate (ECu) nuclei and classified according to their: 1) location within the nuclei, 2) receptive fields, and 3) response to standardized deep layer microstimulation in the forelimb area of the motor (MI) cortex. Excitatory neuronal responses to this MI cortical stimulation ranged in latency from 2-28 msec, with 80% of responses in the 4-12 msec range. Overall, the rostral extremity of the Cu (0.5-1.0 mm rostral to the obex), and the ECu contained the highest percentage of recorded neurons responding to the MI cortical stimulation (61%). By contrast, only 11% responded in the middle subregion of the Cu (+0.4 to -0.9 mm relative to the obex), and 28% responded in the caudal-most subregion (1.0-2.0 mm caudal to obex). A similar paradigm was used to investigate the topography of MI corticofugal modulation of afferent transmission through the Cu and ECu. The MI cortical stimulation was used as a conditioning (C) stimulus in a condition-test (C-T) paradigm in which the test (T) stimulus was standardized mechanical vibration of digit No. 4 of the contralateral forepaw. A total of 30 cells from different subregions were analyzed by measuring the averaged evoked unit responses to the T-stimuli, and plotting them as a function of C-T intervals from 0-50 msec.(ABSTRACT TRUNCATED AT 250 WORDS)
    Brain Research Bulletin 03/1989; 22(2):245-52. DOI:10.1016/0361-9230(89)90049-X · 2.97 Impact Factor

Publication Stats

306 Citations
42.80 Total Impact Points

Institutions

  • 1993–2000
    • Hallym University
      • • College of Medicine
      • • Department of Medicine
      Sŏul, Seoul, South Korea
  • 1997
    • Yonsei University
      Sŏul, Seoul, South Korea
  • 1990
    • Harvard Medical School
      • Department of Anesthesia
      Boston, Massachusetts, United States
    • Brigham and Women's Hospital
      • Department of Medicine
      Boston, Massachusetts, United States